In today's electrical supply systems, there are occasions when alternate sources of electric power are necessary or desirable. For example, the capability of switching from utility power to emergency generator power is extremely important for many businesses, hospitals and industries, and is also being employed in residential applications.
In certain applications, it is desirable for separate electrical circuits or even separate groups of electrical circuits to be arranged so that when one group of circuits is switched to a conductive state, another group of circuits is switched to a non-conductive state in alternating fashion. In some arrangements, it may be desirable to alternately switch a common load between separate power sources so that as one power source is disconnected from the load, the second power source is simultaneously connected to prevent any or minimal interruption of power to the load. In order that the desired period of alternate switching may be effective essentially simultaneously, a need has been recognized to employ a coupling mechanism which functions to switch one group of circuits OFF as the other group of circuits is switched ON.
It remains desirable to provide a mechanism which automatically turns one circuit breaker OFF when an adjacent circuit breaker is turned ON. Such a mechanism should assure that the main contacts of both circuit breakers cannot be closed at the same time. It is also desirable that the mechanism does permit, however, both of the circuit breakers to be switched OFF at the same time.